Pawl-and-ratchet device



woman.

E. PASSMORE.

Pawl and Ratchet Device. No. 233,636. Patented Oct. 26, 1880.

WITNESSES:

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STATES Y NrrE PATENT Eric.

PAWL-AND-RATCH ET DEVICE.

SPECIFICATION forming part of Letters Patent No. 233,636, dated October 26, 1880,

Application filed September 25, 1880.

I of the city and county of Philadelphia, in the State of Pennsylvania, have invented certain new and useful Improvements in Pawl-and- Ratchet Devices, of which improvements the following is a specification.

My invention relates to that class ofsnch devices in which a cup is provided with projections or shoulders, forming ratchet-teeth around its inner surface, and fitted with a capplate turning freely in the open end of the cup upon a shaft projecting through the cap-plate and through the bottom of the cup. The capplate is secured, by means of a pin or otherwise, to the inner end of this shaft, the outer end of which carries a pinion that engages with the driving mechanism. A short sleeve projecting from the cap-plate and a longer sleeve projecting from the bottom of the cup afford bearing to the shaft. A collar on the inside of the cap-plate determines the depth of the-space between the under side of the plate and the inner side of the bottom of the clip. In this space two detents or pawls are pivoted in the cap-plate on opposite sides of the shaft, the pivots being near the ends of the pawls, so that each of the pawls plays freely under the cap-plate on its pivoted end, and its free end will either drop downward and outward so as to catch against one of the projections or shoulders on the interior of the cup, or will drop inward toward the shaft until it rests upon the collar above mentioned without engaging with the projections on the interior of the cup, according to the direction in which the shaft is turned. In the former case the driving mechanism will be operative; in the latter case it will not be operative.

In operating such devices, as applied to lawnmowing machines, I have found that in whichever direction the shaft is revolved the free ends of the pawls tend to fall suddenly, by gravitation, alternately outward and inward toward the circumference and toward the center of the cup, and in these movements, as they have free play on their pivots and between the cap-plate and the bottom of the cup, they alternately strike the cup and the shaft with a rattling noise that is particularly objectionable. Moreover, there are various conditions (No model.)

which may interfere with their catching against the projections in the cup.

It is the object of my invention to insure the positive protrusion of these pawls in the forward movement of the shaft, and also to insure their positive withdrawal from their engagement with the teeth in the backward movement of the shaft, and to effect both movements without the rattling heretofore attending them, thereby making the device practically noiseless.

To these ends my invention consists in combining with a pawl-and-ratchet device of the above-described class a plate interposed between the faces of the pawls and the bottom of the cup, and guides interposed between the back of the pawls and the side of the cup, this plate and these guides constituting what I will designate as a switch 5 and I willnow particularly describe my invention with reference to the accompanying drawings, which form part of this specification, and in which Figure l is a front elevation of the pawland-ratchet device with my improvement applied thereto, showing the pawls drawn inward by the action of the switch. Fig. 2 is a similar view, showing the pawls protruded by the action of the switch. Fig. 3 is a view, in perspective, of the switch in detail and Fig. 4 is a similar view of the switch with the pawls pivoted in the cap-plate and the capplate pinned to the shaft, as hereinbefore described, the pawls being drawn inward, as in Fig. 1.

The cup A, Figs. 1 and 2, has ratchet-teeth or shoulders to a on its interior surface, and I have shown flanges A on its exterior as a means of connecting with the device the spiral cutters of a lawn-mower.

The shaft B passes through a hushed opening in the center of the bottom of the cup A, and has its bearin g in a sleeve projecting from the bottom of the cup, which sleeve is shown in elevation at A Figs. 1 and 2. The inner end of the shaft carries a cap-plate, E, which is secured upon it by means of a collar and pin, as shown in Fig. 4. A pinion mounted on the outer end of the shaft gives motion to the shaft.

The gravitation-pawls G G are, as shown in Figs. 1, 2, and 4, provided each with a pivot,

0 c, projecting from its upper surface near one end, and each has a curved outline at the back and an angular termination of its free end.

The cap-plate E shown in the drawings only partially closes the cup; but I contemplate making it an entire circle or disk fitting into the cup and turning freely therein. In addition to the sleeve 12 on its outside, as already mentioned, this eapplate has a collar on its inner side fitting over the shaft B, and resting upon the bushing in the bottom of the cup A, so as to support the cap-plate. The space between the cap-plate and the bottom of the cup is such as to accommodate the switchplate and the pawls and to permit of their working in this space, as will presently be described.

The pivots c 0 on the pawls are provided with bearings in the cap-plate, as shown in Fig. 4.

"he switch D, Fig. 3, consists of a fiat annular plate, 1), to fit loosely in the bottom of the cup A. Upon this plate are two guides, (1 cl, the depth of each guide being equal to the thickness of the pawls, and the form of the guide corresponding with that of the curved back of the pawl. One end of the guide coincides with the edge of the plate I), while the other end is abruptly curved inward from the edge of the plate, so as to form a shoulder, against the inner side of which the pivoted end of one of the pawls will rest, while its outer side will act as a deflector to protrude the free end of the other pawl. These guides are placed on opposite sides of the plate, the open end of one guide being opposite the shoulder of the other, as shown. When this switch is in position it will be seen (Fig. 4) that the plate D is interposed between the faces of the pawls and the bottom of the cup, while the guides are interposed between the backs of the pawls and the side of the cup.

The pawl (J rests in the guide (1 and the pawl O in the guide at, the plate D holding the pawls snugly up to the cap-plate and the guides holding the pawls respectively close up to the shaft. With the revolution of the shaft toward the left hand the pawl G will be carried round out of the guide (Z before the switch D begins to move, and its free end will come against the shoulder on the guide 61, by which it will be positively protruded until it catches against one of the teeth in the cup. Meanwhile the free end of the pawl G will have been moved round out of its guide d and deflected by the shoulder of the guide (1 until it has caught against another of the ratchetteeth, (see Fig. 2;) and the shaft being thus locked, its further movement will operate the cup and its attached mechanism. Upon reversing the shaft the cap-plate will carry the pawls back again into their respective guides, where they will be snugly retained until the movement of the shaft is again reversed.

It will be seen that in both the outward and the inward movements of the pawls the guides serve to graduate their protrusion and withdrawal, and the pawls no longer play out or in so freely as to strike against the cup or the shaft with the rattling noise which would otherwise attend these sudden movements.

When the pawls are resting in the guides, as seen in Fig. 1, if the movement of the shaft is reversed the cap-plate will carry the pawl C out of the guide d and against the shoulder of the guide (1 before the M8 inertia, of the switch D has been overcome. So, again, if the shaft is turned backward when the pawls are in the position shown in Fig. 2,. the plate D will remain stationary until the cap-plate will have brought the pawls back again within their respective guides, and thus the pawls are moved positively in either direction without possibility of failing to lock or to unlock the shaft, as the case may be.

I do not limit myself to the particular switch herein described, as a plate and guides of other form and construction may be substituted for those shown in the drawings; but,

Having thus described the nature and object of my improvements,what I claim as new, and desire to secure by Letters Patent, is-

1. As an improvement in pawl-and-ratchet devices substantially such as hereinbefore de scribed, the combination, with the cup and the pawls, of a switch, substantially as and for the purposes described.

2. In pawl-and-ratchetdevices substantially such as hereinbefore described, a plate interposed between the pawls and the bottom of we the cup and guides interposed between the pawls and the cup, substantially as and for the purposes described.

EVERETT G. PASSMORE.

Witnesses J. WALTER DOUGLASS, GEO. F. FINDLAY. 

